The present invention relates to micro-manipulators, and particularly to micro-manipulators that use gripping fingers to grip resilient micro-material.
Conventionally, micro-manipulators are used to assemble micro-parts or to handle cells. Generally, a micro-manipulator has a gripping mechanism for moving the leading ends of gripping fingers to grip micro-objects. (See patent publication 1, for example) Also, because the material to be gripped is minute, an operator observes at the object through a microscope with the naked eye, or observes images of the object output to a monitor such as a display via a camera mounted on the microscope, in order to operate the micro-manipulator. (See patent publication 2, for example)
If the micro-material to be gripped is derived from a living body, such as a cell, the micro-manipulator needs to be operated while visually checking the degree of deformation of the cell, in order to avoid damaging it with excessive gripping forces. Specifically, in order to prevent flicking metallic micro-material or crushing micro-material such as a cell when the gripping force is too great, resilient means and current restricting means have been applied to limit the operation and control the maximum gripping force.    [Patent Publication 1] Tokkai Hei 8-168979    [Patent Publication 2] Tokkai Hei 4-303810
However, the operation of conventional micro-manipulators is such that the resilience of the micro-material, in other words, the hardness or softness of the object, is unknown to the operator as the micro-material is gripped while an operator viewed it on a screen. For that reason, the operator does not know exactly how much force to apply to the grippers when gripping the micro-material. For example, when gripping a metallic micro-material and too much force is applied, the metallic micro-material tends to be undesirably flicked away. If handling a micro-material such as a cell, too much applied force tends to crush the cell.
In view of the above-described shortcoming, it is an object of the present invention to provide a micro-manipulator that can appropriately grip resilient micro-material and which can ascertain the resilience value of the micro-material.